Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
  • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
  • C23C14/18—Metallic material, boron or silicon on other inorganic substrates
  • C23C14/185—Metallic material, boron or silicon on other inorganic substrates by cathodic sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/56—Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks
  • C23C14/564—Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268

Definitions

• the present invention relates to a high-purity copper or high-purity copper alloy sputtering target, a process for manufacturing the foregoing sputtering target, and a high-purity copper or high-purity copper alloy sputtered film.
• % and ppm as used herein respectively represent “mass%” and “mass ppm”.
• purity represents the purity excluding C, O, N and H as gas components.
• the sputtering method is to form a film on a substrate by utilizing the phenomenon where atoms configuring the target are discharged into space and accumulated on the opposing substrate based on the momentum exchange that occurs when the accelerated charged particles collide with the target surface.
• the sputtering target is usually in the shape of a discoid or rectangular plate, and is used as the sputter source for forming, on the substrate, an electrode, gate, element, insulating film, protective film and the like for various semiconductor devices by way of sputtering.
• an aluminum and aluminum alloy target a copper and copper alloy target, a high-melting-point metal and alloy target, a metal silicide target and the like are used.
• an important target is a copper and copper alloy target that is used in forming a copper wiring as an alternative of a conventional aluminum wiring.
• nodules protrusions having a size of several ⁇ m to several mm, referred to as nodules, sometimes arise on the eroded portion of the sputtering target.
• nodules will burst as a result of colliding with the charged particles during the sputtering process, and thereby cause the generation of particles (cluster-state coarse fragments) on the substrate.
• the generation of particles will increase in proportion to the amount of nodules on the eroded surface of the target, and a major issue is to prevent the generation of nodules in order to reduce the problematic particles.
• particles directly adhere to the thin film that is formed on the substrate, or once adhere to and accumulate on the peripheral wall or component of the sputtering device and thereafter flake off and once again adhere to the thin film; and it causes problems such as the disconnection or short circuit of the wiring.
• the generation of particles is becoming a major problem pursuant to the advancement of higher integration and miniaturization of the electronic device circuit as described above.
• Patent Document 1 describes cleaning electrolyte based on solvent extraction.
• Patent Document 2 describes eliminating Sb and Bi with chelate resin.
• Patent Document 3 describes adding a diaphragm and glue in copper electrolysis to smooth the electrolyzed surface, and thereby reducing the uptake of impurities.
• Patent Document 4 describes bringing anolite into contact with activated carbon in copper electrolysis to eliminate glue.
• Patent Document 5 describes performing electrolysis once again in copper electrolysis.
• Patent Document 6 describes smoothing the electrode surface based on periodic reverse-current electrolysis in copper electrolysis to prevent the inclusion of suspended solids and electrolyte.
• Patent Document 7 describes adding a macromolecular additive to improve the surface condition and using electrolyte containing urea in copper electrolysis to produce high-purity copper with a low silver and sulfur content.
• Patent Document 8 describes that the three metallurgical characteristics of a sputtering target affecting the performance of the target are: the uniformity of the material (no precipitate, void, inclusion and other defects); crystal grain size (finer crystal grain size is generally more preferable than coarse crystal grain size); and texture (texture relates to the strength of a specific crystallographic orientation, that is, a "weak” texture includes substantially random distribution of the crystallographic orientation, and a "strong” texture includes a preferential crystallographic orientation in the distribution of the crystallographic orientation). Patent Document 8 further describes that it is generally necessary to reduce defects such as inclusions in the target.
• Patent Document 9 discloses a titanium sputtering target in which the number of inclusions of 1 ⁇ m or more existing at the crystal grain boundary of titanium configuring the target is 100 inclusions or less per 1cm 2 of the target plane. Patent Document 9 additionally describes that the inclusions existing at the crystal grain boundary of titanium are a composite compound based on a combination of one or more types among oxides, nitrides, carbides, sulfides, and hydrides of metal components of titanium or iron, nickel, chromium, aluminum, silicon, tungsten and molybdenum, and that the oxides can be decomposed by heat treatment.
• Patent Document 10 and Patent Document 11 describe that the number of inclusions in an aluminum or aluminum alloy target is reduced to be 40 inclusions/cm 2 or less per unit area; splashes can be reduced by bringing the maximum length of the inclusions to 20 ⁇ m or less; to reduce the inclusions in the sputtering target is particularly important in order to inhibit the generation of particles and splashes; and inclusions are reduced by filtering molten metal with a ceramic filter.
• Patent Document 12 discloses a high-purity copper or copper alloy sputtering target, wherein the target has an oxygen content of 100ppm or less, a carbon content of 150ppm or less, a nitrogen content of 50ppm or less, and a sulfur content of 200ppm or less, or the number of indications having a flat-bottomed hole diameter of 0.5mm or more is 0.014 indications/cm 2 or less on an ultrasonic inspection performed from the target surface; and a process for manufacturing a high-purity copper or copper alloy sputtering target having an oxygen content of 100ppm or less, a carbon content of 150ppm or less, a nitrogen content of 50ppm or less, and a sulfur content of 200ppm or less, wherein used is a high-purity copper or copper alloy ingot obtained by melting and casting based on electron beam melting or vacuum induction skull melting.
• inclusions large enough to be detected on the ultrasonic inspection are not observed in current high-purity copper targets.
• Patent Document 13 describes that oxygen, nitrogen and carbon as gas components contained in the copper alloy sputtering target form inclusions at the crystal grain boundary and cause the generation of particles, and that it is desirable to reduce such gas components as much as possible since they cause the unexpected generation of particles during the sputter life. Patent Document 13 also describes that unavoidable impurities excluding gas components are reduced to 10wtppm or less.
• Patent Document 14 discloses copper sputtering targets with a 6N or higher purity.
• the purity and structure of the target must be improved in order to inhibit the generation of particles and, needless to say, the raw material itself must be of high purity.
• the selection of the raw material is important, there is a high possibility of incorporation of impurities during the process of producing the target.
• Nonmetal inclusions exist even in a high-purity copper target having a purity level of 6N or even 7N.
• Nonmetal inclusions of oxide system such as alumina and magnesia were generally considered as the harmful impurities. These elements need to be reduced as a matter of course, but it has been discovered that, rather than the foregoing oxide system inclusions, carbon system inclusions particularly have an adverse effect in the process of producing copper wirings (especially those which are 0.18 ⁇ m or less) of semiconductor devices. These inclusions get mixed as particles in the film that is formed by sputtering the target containing the foregoing nonmetal inclusions.
• the carbon system inclusions are more likely to have an adverse effect.
• the reason for this is because, for instance, if graphite is incorporated as particles in the film that is formed by sputtering, since it has low electrical resistance, it is difficult to detect the wiring portion containing the particles, and it may not be possible to detect such particles as defects.
• measures were not taken for eliminating such carbon system inclusions (especially graphite) in advance.
• oxide system inclusions can be easily eliminated with CMP (Chemical Mechanical Polishing) during the process of forming the wiring after deposition, since carbon system inclusions (especially graphite) are chemically stable, they tend to remain without being eliminated and become a nuisance once they are incorporated in the film.
• CMP Chemical Mechanical Polishing
• the used target was checked.
• a liquid particle counter even though it was a high-purity copper target having a purity of 6N and a carbon content of 1ppm or less, nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less were detected in a quantity of approximately 60,000 inclusions/g in the target structure.
• the foregoing nonmetal inclusions or the carbon system inclusions of carbon or carbide were measured with the "light scattering automatic particle counter for liquid" (manufactured by Kyushu RION Corporation).
• the measurement method is based on sorting the particle size in the liquid and measuring the particle concentration and particle count.
• the foregoing measuring equipment is also known as a “liquid particle counter” and is based on JIS B 9925 (this measuring equipment is hereinafter referred to as the "liquid particle counter").
• the target structure 5g of the target structure were sampled and slowly dissolved in 200c of acid so that the inclusions will not be dissolved, it is diluted with deionized water to be 500cc, and 10cc of this was taken and measured with the liquid particle counter. For example, if the number of inclusions is 800 inclusions/cc, this means that 0.1g of the sample was analyzed in 10cc, and the number of inclusions will be 8000 inclusions/g.
• an object of the present invention is to reduce the percent defect of wirings of semiconductor device during sputter deposition so as to ensure favorable repeatability, as a result of using high-purity copper or high-purity copper alloy from which harmful inclusions of P, S, C and O system have been reduced as the raw material, controlling the existence form of nonmetal inclusions in the raw material, in particular reducing carbon system inclusions, and thereby improving the purity and the structure of the high-purity copper or high-purity copper alloy target itself.
• the present inventors made the following discovery. Specifically, the present inventors discovered that it is possible to reduce the percent defective of wirings of semiconductor device that were formed by sputtering a high-purity copper or high-purity copper alloy target, as a result of reducing the abundance of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less in high-purity copper and high-purity copper alloy, and additionally reducing carbon system inclusions.
• the present invention provides:
• the present invention additionally provides:
• the present invention also provides:
• P, S, O and C are particularly problematic as impurities that cause the generation of inclusions. Since the solubility of these elements in copper is extremely low, many of these become inclusions in copper. Particularly in achieving a high-purity copper of the present invention, it is a taboo to add organic additives such as glue or polymer for smoothing or the like as is conventionally done. This is because the addition of such additives will increase the existence of P, S, O and C.
• electrolyte of a sulfuric acid system that particularly causes incorporation of nonmetal inclusions, in particular S was not used, and electrolyte of nitric acid or hydrochloric acid system was used. Nevertheless, even when taking the foregoing measures, the inclusion of large amounts of P, S, O and C as impurities was acknowledged. Thus, it was necessary to seek the cause of increase in impurities elsewhere; that is, other than the increase due to electrolyte itself.
• SiO 2 , C (carbon and carbide), and AS 2 O 3 may be incorporated by: elution of organics from electrolytic device, particularly pipes or the like for supplying and circulating the electrolyte, into the electrolyte during electrolytic refining; circumstances in which the electrolytic device is placed; and the adhesion to the anode.
• P, S and O contained in the electrolyte exist as the suspended solids of CuP, CuS and CuO, and it has also been discovered that these suspended solids are sometimes caught in the copper during the electrolysis at the cathode, and that these suspended solids are the primary cause of contamination.
• the impurities are organics
• the electrolytic copper containing organics of several ppm or more in a high concentration is to be melted by way of high frequency melting in order to achieve high purity
• carbon (C) that is formed as a result of the decomposition of the organics will be incorporated in the melted copper as is, or as carbide.
• nonmetal inclusions refers to the solids existing in the copper structure. Once these solids are incorporated, they cannot be sufficiently eliminated in the melting process.
• carbon or carbide having carbon as its component is particularly harmful as described above.
• carbon or carbide is incorporated during the semiconductor production process, it becomes extremely difficult to eliminate such carbon or carbide.
• impurities cause defects in the semiconductor equipment and become even a greater problem pursuant to the miniaturization of such semiconductor equipment.
• an important process for eliminating impurities on a raw material level is to provide a diaphragm between the anode and the cathode and pass the electrolyte extracted from the anode-side electrolytic cell (anode box) or the additional electrolyte through an activated carbon filter immediately before supplying such electrolyte to the cathode-side electrolytic cell (cathode box), and thereafter to supply the electrolyte to cathode-side electrolytic cell in order to perform electrolytic refining.
• the electrolytic production process for producing the high-purity copper was described above, and the high-purity copper of the present invention can only be obtained with the foregoing process.
• the starting material a commercially available high-purity copper material having a purity level of 5N or less can be used. Nevertheless, this starting material contains metal components other than Cu, nonmetal components (SiO 2 , Al 2 O 3 and so on), P, S, O, C and their compounds (CuP, CuS, CuO and so on) each in the amount of several ppm to several thousand ppm.
• the high-purity copper of the present invention uses the foregoing starting material as the raw material; it is desirable to yield a high-purity copper of which the purity is 6N or higher and in which the content of the respective components of P, S, O and C is 1ppm or less and the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less is 10,000 inclusions/g or less, more preferably 5,000 inclusions/g or less.
• the components of P, S, O and C all become impurities in copper and form phosphides, sulfides, carbides and oxides that do not become a solid solution in the copper, and these may cause the formation of nonmetal inclusions.
• these components of 1ppm or less respectively, the nonmetal inclusions can be reduced and the characteristics of high-purity copper can improve.
• the high-purity copper produced as described above is used to prepare a target.
• the present invention is to bring the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less contained in the high-purity copper or high-purity copper alloy sputtering target to 30,000 inclusions/g or less, and the volume of such nonmetal inclusions is the problem. If the number of nonmetal inclusions in the high-purity copper or high-purity copper alloy as the raw material exceeds 10,000 inclusions/g, the nonmetal inclusions in the target will reach a level of becoming problematic and become protrusive foreign matter during the erosion of the target, and abnormal discharge is easily generated at such protrustive foreign matter. This causes the generation of particles during sputtering.
• the value of 30,000 inclusions/g or less is not necessarily a large amount. This value cannot be achieved simply by reducing the content of impurities configuring the nonmetal inclusions to be 1ppm or less.
• the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less is 15,000 inclusions/g or less.
• the existence of inclusions of carbon or carbide is harmful, and it is desirable to reduce the nonmetal inclusions containing carbon or carbide having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less to 15,000 inclusions/g or less. It is more preferable to reduce such inclusions to 10,000 inclusions/g or less, and even more preferable to reduce those to 5,000 inclusions/g or less so that it will be 50% or less of the overall nonmetal inclusions. Since the carbon or carbide is often contaminated from organics as described above, the use of organics in electrolytic refining must be avoided.
• a high-purity copper alloy sputtering target can be produced by additionally adding an alloy element to the foregoing high-purity copper as the base material.
• the sputtering target may be produced by adding one type or two types or more among the normally added elements of Al, Ag, B, Cr, Ge, Mg, Mn, Nd, Si, Sn, Ti and Zr to the high-purity copper at a rate of 10% or less.
• high-purity copper materials and the aforementioned alloy component materials may be used as the raw material of the high-purity copper or high-purity copper alloy to be used in producing the sputtering target of the present invention.
• radioactive elements such as U and Th as impurities affect the MOS with their radiation, alkali metals and alkali earth metals such as Na and K deteriorate the MOS interface characteristics, and transition metals or heavy metals such as Fe, Ni and Co generate an interface state or cause a junction leak. These elements may contaminate the semiconductor equipment through the copper film.
• a target is usually prepared by melting and casting the raw material, performing plastic forming processes such as forging and rolling as well as heat treatment in order to achieve the appropriate crystal structure, particle size and the like of the cast material, and performing finish processing to obtain the final target size in a discoid shape or the like.
• the quality of the target such as its crystal orientation can be controlled by appropriately combining the plastic forming process such as forging and rolling, and the heat treatment process.
• the primary inclusions in the copper and copper alloy are oxides, nitrides, carbides and sulfides, and they are generated during the process of melting and casting the raw material.
• melting and casting are performed in a nonoxidizing atmosphere, or preferably in a vacuum for efficiently eliminating oxygen, nitrogen and sulfur as the inclusion sources.
• electron beam melting using a water-cooled copper crucible is suitable in order to avoid the contamination of carbon and oxygen from the graphite crucible that is used in conventional high frequency melting.
• the vacuum arc remelting process it is preferable to use the high-purity copper as the electrode, and it is further preferable to use high-purity copper with as few inclusions as the melted raw material. Moreover, with the cold crucible melting process, it is also effective to add the arc melting function of using the high-purity copper as the electrode in order to assist the melting process.
• the reduction of impurities and inclusions of the target is reflected in the thin film, and a thin film having the same inclusion level of impurities and inclusions as the target can be obtained.
• the target raw material preferably used is high-purity copper of which the purity is 6N or higher and in which the content of the respective components of P, S, O and C is 1ppm or less and the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less is 10,000 inclusions/g or less.
• 4N-Cu was used as the raw material anode and electrolytic refining was performed using electrolyte of nitric acid series.
• electrolysis was performed by separating the cathode and the anode with a diaphragm, extracting the Cu ion-containing electrolyte that was eluted from the anode, and passing it through an activated carbon filter immediately before being put into the cathode box.
• the number of detected nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less was 8,000 inclusions/g.
• the contents of P, S, O and C in the electrodeposited copper were 1ppm or less respectively.
• 50kg of the raw material was subject to cold crucible melting to obtain an ingot, further subject to the processes of homogenization heat treatment, forging, rolling, and heat treatment to produce a sputtering target.
• Conventional methods may be used as the processes of homogenization heat treatment, forging, rolling, and heat treatment of the target.
• the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less was 20,000 inclusions/g.
• 40% was inclusions of the carbon system (including carbon and carbide).
• the number of carbon system inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less was 8000 inclusions/g.
• the number of particles having a particle size of 0.05 ⁇ m or more was 17 particles/square inch.
• the number of carbon system particles having a particle size of 0.05 ⁇ m or more was small at 10 particles/square inch, and a favorable sputtered film was obtained.
• Example 1 50kg of the same raw material as Example 1 was subject to a combination of cold crucible melting and vacuum induction melting to prepare an ingot, and similarly subject to the processes of homogenization heat treatment, forging, rolling, and heat treatment to produce a sputtering target.
• the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less was 10,000 inclusions/g.
• 30% was inclusions composed mostly of the carbon system (including carbon and carbide). Specifically, the number of carbon system inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less was 3000 inclusions/g.
• the number of particles having a particle size of 0.05 ⁇ m or more was 8 particles/square inch.
• the number of carbon system particles having a particle size of 0.05 ⁇ m or more was small at 4 particles/square inch, and a favorable sputtered film was obtained.
• Example 1 50kg of the same raw material as Example 1 was melted by way of vacuum induction melting using a high-purity and high-density graphite crucible to prepare an ingot.
• the ingot was subject to the processes of homogenization heat treatment, forging, rolling, and heat treatment to produce a sputtering target.
• the number of nonmetal inclusions having a particle size of 0.5 ⁇ m or more and 20 ⁇ m or less was large at 40,000 inclusions/g.
• the number of particles having a particle size of 0.05 ⁇ m or more was 80 particles/square inch.
• the number of carbon system particles having a particle size of 0.05 ⁇ m or more was 60 particles/square inch.
• a high-purity copper or high-purity copper alloy from which harmful inclusions of P, S, C and O system have been reduced.
• the present invention is effective as a high-purity copper and copper alloy target suitable for forming a copper wiring or the like that is capable of preventing problems such as short circuits and disconnections.

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